1. Field of the Invention
The present invention relates to a glass-ceramic plate in which at least one opening is made which is especially intended to house an atmospheric gas burner.
2. Description of the Related Art
Gas cookers or hobs which include gas burners fixed in a metal stand such as a frame or housing are known. In this type of cooking device, a glass plate, generally toughened and made of ceramic or glass-ceramic, covers the peripheral surface of each of the burners. In order not to have to apply force to the plate when mounting it to a burner, which would run the risk of breaking the plate, each opening made in the plate for this purpose is significantly wider than the diameter of the corresponding burner. The large circular gap thus created between the plate and the gas burner is covered with a circular metal collar. The latter ensures that there is mechanical separation which prevents direct contact between the plate and the metal burner, such direct contact being likely to generate cracks in the plate which impair its mechanical strength.
Although fitting a burner into the plate in this way makes it possible to decrease the risk of forming cracks in the plate, this risk nonetheless remains, because of the contact between the collar and the plate. Moreover, this type of fitting has a not insignificant drawback since sealing is not well provided for, and liquids which can spill out from cooking pans may flow between the plate and the metal collar.
Apart from the fact that cleaning this type of fitting is difficult and also often requires at least part of the device to be dismantled, the ingress of liquid under the plate can be dangerous, especially when there are one or more electrical appliances, for example in the configuration in which the cooker is of the combination type which includes heating elements such as radiant or halogen elements.
Improvements have already been proposed. Thus, it is known from EP 715,125 to mount the gas burner into the corresponding opening in the glass-ceramic plate by interposing between them a metal collar in the form of an eyelet which overlaps the edge of the opening and which thus provides mechanical protection. Further, sealing is provided by means of a ring-polished graphite piece positioned at the interface between the plate and the metal collar.
Although such a system is satisfactory with regard to mechanical strength and sealing, it is complicated to fit and cannot be dismantled by the user. Furthermore, the plate cannot be fully cleaned as the edge of the opening is covered. Finally, the cost of the metal cover is relatively high, especially as it consists of a number of components manufactured by drawing and because it makes use of a number of complementary seals or inserts, resulting in a not insignificant increase in the cost of the entire cooker.